Rav was a descendant of a distinguished Babylonian family which claimed to trace its origin to Shimei, brother of King David (Sanhedrin 5a; Ketubot 62b). His father, Aibo, was a brother of Chiyya, who lived in Palestine, and was a highly esteemed scholar in the collegiate circle of the patriarch Judah I. From his associations in the house of his uncle, and later as his uncle's disciple and as a member of the academy at Sepphoris, Rav acquired such an extraordinary knowledge of traditional lore as to make him its foremost exponent in his native land. While Judah I was still living, Rav, having been duly ordained as teacher—though not without certain restrictions (Sanhedrin 5a)—returned to Babylonia, where he at once began a career that was destined to mark an epoch in the development of Babylonian Judaism.
In the annals of the Babylonian schools the year of his arrival is recorded as the starting-point in the chronology of the Talmudic age. It was the 530th year of the Seleucidan and the 219th year of the common era. As the scene of his activity, Rav first chose Nehardea, where the exilarch appointed him agoranomos, or market-master, and Rabbi Shela made him lecturer (amora) of his college (Jerusalem Talmud Bava Batra v. 15a; Yoma, 20b). Then he removed to Sura, on the Euphrates, where he established a school of his own, which soon became the intellectual center of the Babylonian Jews. As a renowned teacher of the Law and with hosts of disciples, who came from all sections of the Jewish world, Rav lived and worked in Sura until his death. Samuel, another disciple of Judah I, at the same time brought to the academy at Nehardea a high degree of prosperity; in fact, it was at the school of Rav that Jewish learning in Babylonia found its permanent home and center. Rav's activity made Babylonia independent of Palestine, and gave it that predominant position which it was destined to occupy for several centuries.
The method of treatment of the traditional material to which the Talmud owes its origin was established in Babylonia by Rav. That method takes the Mishnah of Judah ha-Nasi as a text or foundation, adding to it the other tannaitic traditions, and deriving from all of them the theoretical explanations and practical applications of the religious Law. The legal and ritual opinions recorded in Rav's name and his disputes with Samuel constitute the main body of the Babylonian Talmud. His numerous disciples—some of whom were very influential and who, for the most part, were also disciples of Samuel—amplified and, in their capacity as instructors and by their discussions, continued the work of Rav. In the Babylonian schools, Rav was rightly referred to as "our great master." Rav also exercised a great influence for good upon the moral and religious conditions of his native land, not only indirectly through his disciples, but directly by reason of the strictness with which he repressed abuses in matters of marriage and divorce, and denounced ignorance and negligence in matters of ritual observance.
Rav, says tradition, found an open, neglected field and fenced it in (Hullin 110a). Special attention was given by him to the liturgy of the synagogue. He is reputed to be the author of one of the finest compositions in the Jewish prayerbook, the Musaf service of the New Year. In this noble prayer are evinced profound religious feeling and exalted thought, as well as ability to use the Hebrew language in a natural, expressive, and classical manner (Jerusalem Talmud Rosh Hashanah i. 57a). The many homiletic and ethical (haggadistic) sayings recorded of him show similar ability. As a haggadist, Rav is surpassed by none of the Babylonian Amoraim. He is the only one of the Babylonian teachers whose haggadistic utterances approach in number and contents those of the Palestinian haggadists. The Jerusalem Talmud has preserved a large number of his halakic and aggadistic utterances; and the Palestinian Midrashim also contain many of his aggadot. Rav delivered homiletic discourses, both in the Beth midrash (college) and in the synagogues. He especially loved to treat in his homilies of the events and personages of Biblical history; and many beautiful and genuinely poetic embellishments of the Biblical record, which have become common possession of the aggadah, are his creations. His aggadah is particularly rich in thoughts concerning the moral life and the relations of human beings to one another. A few of these utterances may be quoted here: (Shabbat 10b)
Rav loved the Book of Ecclesiasticus (Sirach), and warned his disciple Hamnuna against unjustifiable asceticism by quoting advice contained therein—that, considering the transitoriness of human life (Eruvin 54a), one should not despise the good things of this world. To the celestial joys of the future he was accustomed to refer in the following poetic words: (Berakhot 17a)
Rav also devoted much attention to mystical and transcendental speculations which the rabbis connect with the Biblical account of creation (Genesis 1, Ma'aseh Bereshit), the vision of the mysterious chariot of God (Ezekiel 1, Ma'aseh Merkabah), and the Divine Name. Many of his important utterances testify to his tendency in this direction (Hagigah 12a, Kiddushin 71a).
Concerning the social position and the personal history of Rav we were not informed. That he was rich seems probable; for he appears to have occupied himself for a time with commerce and afterward with agriculture (Hullin 105a). That he was highly respected by the Gentiles as well as by the Jews of Babylonia is proved by the friendship which existed between him and the last Parthian king, Artaban (Avodah Zarah 10b). He was deeply affected by the death of Artaban (226) and the downfall of the Arsacid dynasty, and does not appear to have sought the friendship of Ardeshir, founder of the Sassanian dynasty, although Samuel of Nehardea probably did so. Rav became closely related, through the marriage of one of his daughters, to the family of the exilarch. Her sons, Mar Ukba and Nehemiah, were considered types of the highest aristocracy. Rav had many sons, several of whom are mentioned in the Talmud, the most distinguished being the eldest, Chiyya. The latter did not, however, succeed his father as head of the academy: this post fell to Rav's disciple Rav Huna. Two of his grandsons occupied in succession the office of exilarch (resh galuta) (Hullin 92a).
Rav died at an advanced age, deeply mourned by numerous disciples and the entire Babylonian Jewry, which he had raised from comparative insignificance to the leading position in Judaism (Shabbat 110a, Mo'ed Katan 24a).